Oculus (R)

A cleverly executed mind game that generates scares via structural ingenuity, Oculus suggests a world coming terrifyingly unmoored from its bearings. Set in two separate time periods, director Mike Flanagan's debut boasts sumptuously sweeping, rotating camerawork and a knotty script. It concerns the attempt by Kaylie and younger brother Tim (Karen Gillan and Brenton Thwaites as adults; Annalise Basso and Garrett Ryan as kids) to return to their old home and destroy an ancient mirror that, Kaylie claims, houses a supernatural spirit who was responsible for the deaths of their parents (Rory Cochrane and Katee Sackhoff) 11 years earlier.

Having been rehabilitated in a mental hospital to forget what really happened, the brainwashed Tim is skeptical of Kaylie's theory, and the possibility that Kaylie is delusional is stoked throughout by Flanagan's segueing between the past and present, hallucinations and reality. As this flip-flopping becomes more pronounced, Oculus becomes a swirl of nightmarish confusion in which the unreliability of perception leads characters into danger -- and keeps the action's suspense potent.

Replete with superb performances led by a paranoid Sackhoff and unhinged Cochrane, it's the rare horror film to know how to tease malevolent mysteries and deliver satisfyingly unexpected, unsettling payoffs.